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Expressions of jun B and c‐ fos are enhanced in 4‐nitroquinoline 1‐oxide‐induced rat tongue cancers
Author(s) -
Ohyama Masanobu,
Hirayama Yoshikazu,
Tanuma Junichi,
Hirano Masato,
Semba Ichiro,
Shisa Hayase,
Hiai Hiroshi,
Sugihara Kazumasa,
Kitano Motoo
Publication year - 2004
Publication title -
pathology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
eISSN - 1440-1827
pISSN - 1320-5463
DOI - 10.1046/j.1440-1827.2003.01587.x
Subject(s) - junb , fosb , c fos , immunostaining , tongue , carcinogenesis , biology , immediate early gene , microbiology and biotechnology , 4 nitroquinoline 1 oxide , epithelium , gene expression , pathology , cancer research , gene , immunohistochemistry , medicine , genetics
Activator protein‐1 (AP‐1) is a transcription factor activated in many tumors. Using 4‐nitroquinoline 1‐oxide (4NQO)‐induced rat tongue cancers (TC), the present study investigated the expression levels of genes that encode the components of AP‐1, the jun gene family (c‐ jun , jun B and jun D) and the fos gene family (c‐ fos , fra ‐1, fra ‐2 and fos B). Expression levels of jun B and c‐fos mRNAs in TC were significantly elevated compared with those in epithelial tissue of control rat tongue, although only c‐ fos mRNA levels tended to be elevated in dysplastic tongue epithelium. Histologically, all 4NQO‐induced rat TC were well‐differentiated squamous cell carcinomas. Immunostaining for JunB and c‐Fos proteins was positive in the nuclei of tumor cells of all TC. It is noteworthy that JunB was negative, but c‐Fos was positive in the dysplastic tongue epithelium of the 4NQO‐treated rats. Immunostaining for both proteins was negative in tongue mucosal epithelium of control rats. There were no mutations in the coding regions of either jun B or c‐ fos in all the TC examined. These results suggest the possibility that the expressions of jun B and c‐ fos were enhanced stepwise in 4NQO‐induced carcinogenesis of rat tongue, and that the coexpression of JunB and c‐Fos might play an important role in the establishment of TC.